Without a doubt, changes in political culture tend to start in the state legislature and local governments first. It is usually the rule in any regime.
Barnes is all but giving the Democrats the store. Sure, the South tends to vote more uniformly Republican and, surprise, it was the fastest growing part of the country in the last decade or so.
But then there's the Midwest and Far West more or less split depending on good the state's university system is (no joke). The Northeast meanwhile looks more and more hostile to conservatives. Some Republican officials, such as MA Governor Mitt Romney are bucking this trend, but you know it's a bad sign when "exurban" New Hampshire went for Kerry.
So there you have it. When the economy of the Northeast begins to rev up (which it purportedly will this year), it will pull more Southerners north while the Democrats target "moderate Republicans" such as Lincoln Chafee and Olympia Snowe. Add in close races in PA and VA, and hopefully NV...and the GOP will lose the Senate.
And this assumes that Iraq gets better, and that the public goes along with Bush's more radical domestic reforms. If not, the Holy Republican Trinity could crash and burn like nothing we've ever seen.